This invention relates to a glass fiber sizing composition, a method of applying the sizing composition to the fibers during formation and novel glass fibers for incorporation into resin matrices.
Glass fiber strand is composed of a multitude of fine glass filaments which are formed by being drawn at a high rate of speed from molten cones of glass at the tips of small orifices in a bushing such as is shown in U.S. Pat. No. 2,133,238, incorporated herein by reference. During formation, the filaments are coated while moving at a speed on the order of 1,524 to 6,000 meters per minute with a size which contains a binder to give the strand integrity and workability for any standard textile or reinforcement use. The size also contains a lubricant for the filaments to prevent damage to the strand by abrasion of the individual filaments rubbing against each other or against handling equipment during processing.
Glass fibers in the form of continuous and chopped strand, mat and roving, have found utility in the area of reinforcing resin matrices.
Roving is formed by mounting a plurality of glass fiber forming packages on a creel or support and gathering the strands from the separate packages in parallel, to form a rope or roving. This braided rope or roving is wound on a rotating drum to collect the roving. The roving so produced has a plurality of uses. It can be chopped and separated into separate strands to form chopped strand. It can be woven to form woven roving or it can be used by merely unwinding and impregnating the roving with resin for applications such as filament winding and pultrusion. Roving in whatever form utilized imparts substantial strength to resin composites reinforced therewith.
In order to obtain a glass fiber roving which is acceptable for reinforcement, the formation and processing of the roving must present as few problems in production as possible. The glass fiber strand to form the roving must have integrity in order to tolerate the processing necessary in forming the roving and in subsequent unwinding and chopping operations. Along with the processing properties, glass fiber strand must also demonstrate excellent adhesion to the resin matrix to effectively reinforce the plastic article formed therefrom. Therefore, both the chemical and physical properties of the glass fiber strand in the resin matrix are determined primarily by the sizing composition placed on the strand during formation.
In order to effectively reinforce particular resinous matrices, the sizing composition is usually chemically tailored to be compatible with the matrix. It is the common practice of manufacturers of glass fibers to have strands sized with different sizing compositions for the reinforcement of different varieties of resin matrices, i.e., polyesters, epoxys, vinyl esters, thermoplastics and the like.
In order to increase production efficiencies, it has been desired by the manufacturer's of glass fibers to provide a sizing composition which is effective in the reinforcement of a plurality of resin matrices. Thus, a single sizing composition would be advantageous in limiting the production costs of the sized strand by obviating the need for a multiplicity of sizing compositions for each individual type of resin to be reinforced.
The instant invention provides a sizing composition for glass fiber strand which is useful in the production of fiber reinforced resin matrices.
The invention also provides a sizing composition which is useful for the reinforcement of epoxy, polyester, and vinyl ester resin matrices.
Further, the invention provides a sized glass fiber strand which is easily processed during formation and also subsequent to formation.
Further advantages of the invention will become apparent with the further description thereof.